Displaying lines above grep-ed line

Hi,

How do i display 15 lines above the line that i grep for? Lets say i grep for "searchstring" in a flat file, i want to display 15 lines before the "searchstring" line. is ther a way to do this? Any help is appreciated. Thx in advance.

I was also wondering if i could display to the standard output cretain lines based on their line numbers. For example i could grep a line with its line number using the -n option then i could loop 15 lines before that and display those line. So lets say i grep the line at line number 42, i would -1 the line number and ouput the line at line 41, then -1 again and display line 40....and so on. Is there a way to display string based on specific line numbers? Thnx.

I finally managed to solve the line no problem. I grep-ed the line with the -n option and wrote the output to a file and grepped the line nos and did a while loop to read up and down of the grep-ed line. A bit slow but what the hell....it works